Address feedback from wraith - including constraining state types to class types.

Author: benrr101

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlCommand.Xml.cs

@@ -264,11 +264,11 @@ private IAsyncResult BeginExecuteXmlReaderInternal(
                     AsyncHelper.ContinueTaskWithState(
                         taskToContinue: writeTask,
                         taskCompletionSource: localCompletion,
-                        state: Tuple.Create(this, localCompletion),
-                        onSuccess: static state =>
+                        state1: this,
+                        state2: localCompletion,
+                        onSuccess: static (sqlCommand, localCompletion) =>
                         {
-                            var parameters = (Tuple<SqlCommand, TaskCompletionSource<object>>)state;
-                            parameters.Item1.BeginExecuteXmlReaderInternalReadStage(parameters.Item2);
+                            sqlCommand.BeginExecuteXmlReaderInternalReadStage(localCompletion);
                         });
                 }
                 else

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParser.cs

@@ -12286,9 +12286,9 @@ private Task GetTerminationTask(Task unterminatedWriteTask, object value, MetaTy
                 {
                     return AsyncHelper.CreateContinuationTaskWithState(
                         unterminatedWriteTask,
-                        state1: 0,
+                        state1: this,
                         state2: stateObj,
-                        onSuccess: WriteInt);
+                        onSuccess: static (parser, state) => parser.WriteInt(0, state));
                 }
             }
             else

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/Utilities/AsyncHelper.cs

@@ -137,7 +137,10 @@ internal static void ContinueTask(
         ///     is to allow the task completion source to be continued even more after this current
         ///     continuation.
         /// </remarks>
-        /// <typeparam name="TState">Type of the state object to provide to the callbacks</typeparam>
+        /// <typeparam name="TState">
+        /// Type of the state object to provide to the callbacks, constrained to class types to
+        /// prevent accidental modification of pass-by-value types.
+        /// </typeparam>
         /// <param name="taskToContinue">Task to continue with provided callbacks</param>
         /// <param name="taskCompletionSource">
         /// Completion source used to track completion of the continuation, see remarks for details
@@ -153,6 +156,7 @@ internal static void ContinueTaskWithState<TState>(
             Action<TState> onSuccess,
             Action<TState, Exception>? onFailure = null,
             Action<TState>? onCancellation = null)
+            where TState : class
         {
             ContinuationState<TState> continuationState = new(
                 OnCancellation: onCancellation,
@@ -237,8 +241,14 @@ internal static void ContinueTaskWithState<TState>(
         /// <param name="taskCompletionSource">
         /// Completion source used to track completion of the continuation, see remarks for details
         /// </param>
-        /// <typeparam name="TState1">Type of the first state object to provide to callbacks</typeparam>
-        /// <typeparam name="TState2">Type of the second state object to provide to callbacks</typeparam>
+        /// <typeparam name="TState1">
+        /// Type of the first state object to provide to the callbacks, constrained to class types
+        /// to prevent accidental modification of pass-by-value types.
+        /// </typeparam>
+        /// <typeparam name="TState2">
+        /// Type of the second state object to provide to the callbacks, constrained to class types
+        /// to prevent accidental modification of pass-by-value types.
+        /// </typeparam>
         /// <param name="state1">First state object to provide to callbacks</param>
         /// <param name="state2">Second state object to provide to callbacks</param>
         /// <param name="onSuccess">Callback to execute on successful completion of the task</param>
@@ -252,6 +262,8 @@ internal static void ContinueTaskWithState<TState1, TState2>(
             Action<TState1, TState2> onSuccess,
             Action<TState1, TState2, Exception>? onFailure = null,
             Action<TState1, TState2>? onCancellation = null)
+            where TState1 : class
+            where TState2 : class
         {
             ContinuationState<TState1, TState2> continuationState = new(
                 OnCancellation: onCancellation,
@@ -428,7 +440,10 @@ internal static void ContinueTaskWithState<TState1, TState2>(
         ///     task will be completed with the exception.
         ///   * The task will be completed as successful.
         /// </remarks>
-        /// <typeparam name="TState">Type of the state object to pass to callbacks</typeparam>
+        /// <typeparam name="TState">
+        /// Type of the state object to pass to callbacks, constrained to class types to prevent
+        /// accidental modification of pass-by-value types.
+        /// </typeparam>
         /// <param name="taskToContinue">
         /// Task to continue with provided callbacks, if <c>null</c>, <c>null</c> will be returned.
         /// </param>
@@ -442,6 +457,7 @@ internal static void ContinueTaskWithState<TState1, TState2>(
             Action<TState> onSuccess,
             Action<TState, Exception>? onFailure = null,
             Action<TState>? onCancellation = null)
+            where TState : class
         {
             if (taskToContinue is null)
             {
@@ -533,8 +549,13 @@ internal static void ContinueTaskWithState<TState1, TState2>(
         ///     task will be completed with the exception.
         ///   * The task will be completed as successful.
         /// </remarks>
-        /// <typeparam name="TState1">Type of the first state object to pass to callbacks</typeparam>
-        /// <typeparam name="TState2">Type of the second state object to pass to callbacks</typeparam>
+        /// <typeparam name="TState1">
+        /// Type of the first state object to pass to callbacks, constrained to class types to
+        /// prevent accidental modification of pass-by-value types.
+        /// </typeparam>
+        /// <typeparam name="TState2">
+        /// Type of the second state object to pass to callbacks, constrained to class types to
+        /// prevent accidental modification of pass-by-value types.</typeparam>
         /// <param name="taskToContinue">
         /// Task to continue with provided callbacks, if <c>null</c>, <c>null</c> will be returned.
         /// </param>
@@ -550,6 +571,8 @@ internal static void ContinueTaskWithState<TState1, TState2>(
             Action<TState1, TState2> onSuccess,
             Action<TState1, TState2, Exception>? onFailure = null,
             Action<TState1, TState2>? onCancellation = null)
+            where TState1 : class
+            where TState2 : class
         {
             if (taskToContinue is null)
             {
@@ -667,6 +690,10 @@ internal static void SetTimeoutException(
         /// exception returned is set as the exception that completes the task completion source.
         /// This overload provides a state object to the timeout callback.
         /// </summary>
+        /// <typeparam name="TState">
+        /// Type of the state object to pass to callbacks, constrained to class types to prevent
+        /// accidental modification of pass-by-value types.
+        /// </typeparam>
         /// <param name="taskCompletionSource">Task to execute with a timeout</param>
         /// <param name="timeoutInSeconds">Number of seconds to wait until timing out the task</param>
         /// <param name="state">State object to pass to the callback</param>
@@ -681,6 +708,7 @@ internal static void SetTimeoutExceptionWithState<TState>(
             TState state,
             Func<TState, Exception> onTimeout,
             CancellationToken cancellationToken)
+            where TState : class
         {
             if (timeoutInSeconds <= 0)
             {
@@ -786,14 +814,17 @@ private record ContinuationState<TState>(
             Action<TState, Exception>? OnFailure,
             Action<TState> OnSuccess,
             TState State,
-            TaskCompletionSource<object?> TaskCompletionSource);
+            TaskCompletionSource<object?> TaskCompletionSource)
+            where TState : class;
 
         private record ContinuationState<TState1, TState2>(
             Action<TState1, TState2>? OnCancellation,
             Action<TState1, TState2, Exception>? OnFailure,
             Action<TState1, TState2> OnSuccess,
             TState1 State1,
             TState2 State2,
-            TaskCompletionSource<object?> TaskCompletionSource);
+            TaskCompletionSource<object?> TaskCompletionSource)
+            where TState1 : class
+            where TState2 : class;
     }
 }